Hydrochloric Acid Leaching of Ilmenite

A substitute for rutile can be produced by leaching natural or pre-treated ilmenite in hydrochloric acid. Ilmenite in its natural form is an extraordinarily inactive mineral from which the selective removal of iron is rather difficult. The reactivity of ilmenite so that it can be leached with dilute hydro- chloric acid (=2O% w/w) can be enhanced by pre-treatment steps of oxidation and re- duction. The temperatures at which oxidation and reduction are carried out have an effect on both the kinetics of these steps and the leaching kinetics and optimum temperatures for oxidation and reduction are 950 and 850¦C respectively. The mechanism of leaching of iron from pretreated ilmenite and the effects of rate of agitation, temperature, acid con- centration and addition of ferrous chloride to hydrochloric acid on leaching kinetics and production of fines are discussed in the paper.